This invention relates to wheel and brake assemblies and, more particularly, to a wheel and brake assembly which provides vibration dampening between a torque tube and axle of the assembly.
A typical brake assembly, particularly though not exclusively for use in aircraft, includes a wheel rotatably mounted on an axle, a brake stack comprising rotor and stator discs and a brake actuating mechanism for applying pressure to the brake stack to brake the wheel. The rotor discs are connected to the wheel for conjoint rotation with the wheel and the stator discs are connected to a torque tube which is mounted in a rotationally fixed position. The torque tube of a brake assembly, which is pin mounted to the axle for quick change capability, typically includes a foot extending radially inward to the axle for support by the axle.
During braking operations, the torque tube may experience torsional and axial vibratory movement relative to the axle initiated by the braking torque applied to the torque tube by the brake stack. The vibration of the torque tube may be transmitted throughout the brake assembly, creating not only an excessive amount of noise, but also reducing the life of the brake and potentially causing structural fatigue and failure of aircraft landing gear components, thereby impacting aircraft serviceability, reliability, and maintenance costs.
Previously, attempts have been made to suppress brake vibration through hydraulic dampening, structural modifications such as turnbuckles to load the brake against the landing gear, stiffening of brake and landing gear components, or modification of the brake material. These design changes typically result in increased weight of the aircraft, increased manufacturing costs, and a reduction in reliability. Moreover, the structural devices which provide additional loading between the brake and landing gear require tight manufacturing tolerances for proper installation and operation. Structural variations in the landing gear and brake assembly due to wear or vibration will also reduce the effectiveness of these devices over time.
Prior art brake assemblies also include flange mounted brakes having a dampening plate located between a flange of the axle and the torque tube which are clamped to one another. These dampening devices cannot be used on quick-change pin mounted brakes since the torque tube is not clamped directly to the axle. Instead, an indirect load path must be provided between the torque tube and axle to create a clamping force therebetween to isolate the torque tube from the axle and prevent vibration.